In order to examine the effect of structure on the course of the oxa-dipi-methane rearrangement we are attempting to prepare 17beta-hydroxy-5(10)estrene-2-one by a new synthetic route. In an earlier study we showed that this compound did not yield the oxa-dipi-methane rearrangement product (a cyclopropyl conjugated ketone), however, as the result of latter studies we now wish to examine the sensitized (acetone) photochemistry of this compound.